This parameter is only applicable if printing is
set to cups. Its value is a free form string of options
passed directly to the cups library.
You can pass any generic print option known to CUPS (as listed
in the CUPS "Software Users' Manual"). You can also pass any printer
specific option (as listed in "lpoptions -d printername -l")
valid for the target queue.You should set this parameter to raw if your CUPS server
error_log file contains messages such as
"Unsupported format 'application/octet-stream'" when printing from a Windows client
through Samba. It is no longer necessary to enable
system wide raw printing in /etc/cups/mime.{convs,types}.
"""raw,media=a4,job-sheets=secret,secret"